The present invention relates to an optical device such as a finder device capable of displaying supplementary information in a finder view in a superimposing manner, and a single lens reflex camera on which the finder device is mounted.
In a finder of a single lens reflex camera, a subject image formed on a focusing screen is observed, for example, through a pentaprism. On the subject image thus observed through the finder, information for supplementing the photographing, such as ranging points and ranging areas, is superimposed. Examples of a specific configuration of the finder device capable of superimposing information of this type are described, for example, in Japanese Patent Provisional Publications Nos. HEI 05-127244A (hereafter, referred to as patent document 1), 2002-82278A (hereafter, referred to as patent document 2) and 2000-89336A (hereafter, referred to as patent document 3).
The patent document 1 describes a configuration capable of changing information superimposed on a subject image by controlling orientation of a transmissive liquid crystal disposed in a finder optical system. Each of the patent documents 2 and 3 describes a configuration where ranging information and the like is superimposed on a subject image being observed through the finder, by letting LED (Light Emitting Diode) light representing the ranging information and the like formed by an LED and a mask member enter a pentaprism via a condenser lens and a prism.